VTC Members are encouraged to contribute short project status reports on this page.
New VGOS stations and station upgrades to VGOS
GGAO
GGAO and Westford resumed their VGOS Demonstration Series sessions in November and have observed three more sessions of 1, 5, and 24 hours.
Arthur Niell - 2016 Jan 27
Kokee
Verification and checkout of 12m is under way.
- Trained the KPGO staff on using the 12m signal chain first week of February
- On Feb. 5th successfully obtained fringes on source 1749+096 with GGAO 12m and Westford Broadband system
- On Feb 12th executed a mixed mode observation, between the 12m and the Kk 20 S/X antenna and successfully obtained
fringes. - We are presently exercising the integrated system (Field system control of antenna and backend subsystems).
- This shakedown period is leading to identifying shortcomings in operational manuals and procedures, along
with potential bugs before the acceptance review.
- This shakedown period is leading to identifying shortcomings in operational manuals and procedures, along
- Full summary of the ongoings at KPGO can be found here: http://space-geodesy.nasa.gov/blogs/KPGO/index.html
Chet Ruszczyk - 24 Feb. 2016
Wettzell
- The Eleven feed is installed and tests are ongoing.
- The amplifiers are kept at 17.00 K continously and the feed itself has a temperature of about 10 K. The feed works well and I have done the first G/T measurements with good results. The G/T values are very similar to that of the Triband-feed, which in turn are really good. I tried to measure the Tsys with a small broadband antenna, but my noise diodes have not enough power to calibrate the system. I need to find a more efficient way. I will continue with the measurements as soon as the weather is good enough.
- A problem arises, since the feed is really ultra-broadband. It works down to 500 MHz and it is able to receive GPS, GSM und terrestrical TV-transmitters as well. Therefore we probably need a high-pass filter to avoid the saturation of the postamp and the receiver.
- Christian and Alex have working to setup DBBCs and the Fila10G to connect it to the Mark6 systems and it is now operational, first feedback tomorrow from correlator Bonn; investigations on controlling Mark6 from Field System is ongoing They have solved a few problems, but it is still a lot of work to do there.
Gerhard Kronschnabl and Alexander Neidhardt - 24 Feb 2016
Ishioka
- Operation of Ishioka antenna is now under interruption because of construction of operation building, and will resume after April.
- Modification of cryogenic dewar for QRFH system is being done.
Yoshihiro Fukizaki - 28 Jan 2016
Onsala
Shanghai
Construction of the antenna foundation and tower to be completed by June, with observations starting before the end of this year.
VGOS system will be 16 Gbps, cover 2.7 to 15.5 GHz with 1 GHz bandwidths.
Guangli - 13 Feb 2016
AuScope (Hobart, Katherine and Yarragadee)
Initial testing of Stirling Cycle broadband system has been completed at Hobart. Upgrade of all three sites planned to be completed by the end of 2016.
Currently a prototype receiver is under revision and testing at Callisto. Progressing well. Recently some feed beam pattern measurements have been made to assess the impact of the vacuum window.
A DBBC3 has arrived at Hobart and is installed. Successful tests at 16 Gbps.
S/X mixed-mode observations possible with Hobart 12m. Fringe tests with existing DBBC2s and SX at 2 Gbps successful (Hobart-Yarragadee).
Jim Lovell - 23 Feb 2016
Kashima 34m
We are doing broadband VLBI experiment with our stations(kashima34, Marble1,Marble2) for frequency comparison. We are planning exchange the dish of small antenna from 1.5m/1.6m to 2.4m to improve sensitivity.
Following to the discussion in the previous telecon, we have started communication for broadband test experiment among (NICT,Wettzell,Auscope,Gino-san, and MIT).
Mamoru Sekido - 22 Feb 2016
Yebes
The 13.2m antenna stopped operations (VS observations with the S/X/Ka receiver) on January 8th and is under upgrade works: the backstructure is being covered with cladding and fans are being installed in between the backstructure and the cladding. The three band receiver cryostat is going to be updated with a new head, and a new compressor compatible with the broad boand receiver is beeing installed. All these works are expected to complete in February 18th.
The new broadband receiver with a quadrige horn was mounted in the lab during the third week of January and it will be tested during the next weeks. Preliminary receiver temperature measurements have been performed. The best results (with a balanced amplifier) show receiver temperatures below 25 K between 5.5 and 15 GHz.
4 UDCs have been built and are mostly finished. We have been waiting for the delivey of some filters for some weeks and it is foreseen they will arrive but the end of februrary. Once they are completed they will undergo tests and be installed together with the optical modules in the backends room.
One Mark6 has been received and will be installed during the first week of february. 12 diskpacks 32 TB each have been purchased.
Pablo de Vicente - 28 Jan 2016
S/X Observations with fast antenna network
Two FAST observations were performed in December 2015.
- The first observation coded FAST02 was a 24 hour run starting on December 16th. Four stations took part: Badary (Bv), Yebes (Yj), Wetzell (Wn) and Zelenchuskaya (Zv). Scans were tipically 20 seconds long. DBBC backends at Wn and Yj used DDC mode: 14 channels, 16 MHz each channel. recording rate was 2 Gbps. Frequency setup is the same as R1. Only one polarization. No correlation has been performed yet.
- The second observation coded FAST03 was a 6 hour starting on December 20th. Four stations took part: Badary (Bv), Yebes (Yj), Wetzell (Wn) and Zelenchuskaya (Zv). Scans were tipically 20 seconds long. PFB mode was used in this case: 7 contiguous 32 MHz channels in S band and 7 contiguous 32 MHz channels in X band, only one polarization. Recorded rate was 2 Gbps. No correlation yet.
Pablo de Vicente - 28 Jan 2016
Results from FAST02:
- Fringes to all stations found at S and X bands: Wn, Yj, Bv and Zv. LO difference of 0.99 MHz between Wn, Yj and Bv, Zv were solved at correlation.
- Correlation was done at Bonn and at Kvazar.
- Fringe plots Wn-Yj & Wn-Bv attached.
- SNR plots show that scans 20 seconds long yield a good SNR. An integration time of 10 seconds should still yield results with a good SNR. Plot from Bonn attached.
Pablo de Vicente - 24 Feb 2016
Mixed Mode Observations
Technology Updates
DBBC3
The development activity is mainly concentrated on the realization of the unified control software which connects all the functionalities realised by the different parts of the system.
A number of calibrations are required for each IF and simplification/automatization methods are under test. A number of commands will be added to the control software in order to activate in background such 'continuous' calibrations if required.
The firmware available at present is the DSC full band with bw up to 4 GHz for each IF. PFB with 256 MHz channels is in development, so as DDC with 128-64-32-16-8.
A combination of the three modes will be implemented.
A number of VGOS complete systems (8 IFs) is under construction.
G. Tuccari - 26 Jan 2016
DBBC3 Report
The DBBC unified control software was completed in the main tasks, still remaining to be added the functionality for the DDC and PFB modes,
now possible with low level commands. Completion in its first formal version and testing are under way.
Calibration functionalities are now automated and show to perform well. The entire process is realised in background. The overall speed of the control operations
will be increased.
The complete firmware available at present is the DSC full band with bw up to 4 GHz for each IF.
Activity on the firmware development was concentrated on the DDC implementation so to optimize the functionality and the number of independent bbc elements.
The GPS synchronization was added for the entire set of 8 CORE3H with a single receiver.
The new synthesizer board GCAT has been developed and is in testing phase. It allows to use additional input reference frequencies from the H-Maser (ex. 100MHz)
when this is required.
G. Tuccari - 27 Jan 2016